Originally Posted by SouthArk370Z

Might be easier to hook up a battery charger whilst watching movies.

Originally Posted by SouthArk370Z

I'm not sure what you mean. If you mean remove the fuse (or fusible link) between the two batteries when using just one battery then it would be a good idea to remove the fuse but not really necessary if your wiring is done properly (and you insulate the end that came off the back battery). If you use only one fuse, I would put it close to the front battery; this will help protect the front battery, and the car in general, in case of a short in the inter-battery cable. If you have a short, you may kill the back battery but the car itself should be safe.